It is well-known that the drilling of an oil or gas well, and related operations, is responsible for a significant portion of the costs related to oil and gas exploration and production. In particular, as new wells are being drilled into remote or less-accessible reservoirs, the complexity, time and expense to drill a well have substantially increased.
Accordingly, it is critical that drilling operations be completed safely, accurately, and efficiently. With directional drilling techniques, and the greater depths to which wells are being drilled, many complexities are added to the drilling operation, and the cost and effort required to respond to a problem during drilling are high. This requires a high level of competence from the driller or drilling engineer at the drilling rig (or elsewhere) to safely drill the well as planned.
A “well plan” specifies a number of parameters for drilling a well, and is developed, in part, based on a geological model. A geological model of various subsurface formations is generated by a geologist from a variety of sources, including seismic studies, data from wells drilled in the area, core samples, and the like. A geological model typically includes depths to the various “tops” that define the formations (the term “top” generally refers to the top of a stratigraphic or biostratigraphic boundary of significance, a horizon, a fault, a pore pressure transition zone, change in rock type, or the like. Geological models usually include multiple tops, thereby defining the presence, geometry and composition of subsurface features.
The well plan specifies drilling parameters as the well bore advances through the various subsurface features. Parameters include, but are not limited to, mud weight, drill bit rotational speed, and weight on bit (WOB). The drilling operators rely on the well plan to anticipate tops and changes in subsurface features, account for drilling uncertainties, and adjust drilling parameters accordingly.
In many cases, the initial geological model may be inaccurate. The depth or location of a particular top may be off by a number of feet. Further, since some geological models recite distances based on the distance between two tops, an error in the absolute depth of one top can result in errors in the depths of multiple tops. Thus, a wellbore can advance into a high pressure subsurface formation before anticipated.
Such errors thus affect safety as well as cost and efficiency. It is fundamental in the art to use drilling “mud” circulating through the drill string to remove cuttings, lubricate the drill bit (and perhaps power it), and control the subsurface pressures. The drilling mud returns to the surface, where cuttings are removed, and is then recycled.
In some cases, the penetration of a high pressure formation can cause a sudden pressure increase (or “kick”) in the wellbore. If not detected and controlled, a “blowout” can occur, which may result in failure of the well. Blowout preventers (“BOP”) are well known in the art, and are used to protect drilling personnel and the well site from the effects of a blowout. A variety of systems and methods for BOP monitoring and testing are known in the art, including “Blowout Preventer Testing System and Method,” U.S. Pat. No. 7,706,890, and “Monitoring the Health of Blowout Preventer,” US 2012/0197527, both of which are incorporated herein in their entireties by specific reference for all purposes.
Conversely, if the mud weight is too heavy, or the wellbore advances into a particularly fragile or fractured formation, a “lost circulation” condition may result where drilling mud is lost into the formation rather than returning to the surface. This leads not only to the increased cost to replace the expensive drilling mud, but can also result in more serious problems, such as stuck drill pipe, damage to the formation or reservoir, and blowouts.
Similar problems and concerns arise during other well operations, such as running and cementing casing and tubulars in the wellbore, wellbore completions, or subsurface formation characterizations.
Drills strings and drilling operations equipment include a number of sensors and devices to measure, monitor and detect a variety of conditions in the wellbore, including, but not limited to, hole depth, bit depth, mud weight, choke pressure, and the like. This data can be generated in real-time, but can be enormous, and too voluminous for personnel at the drilling site to review and interpret in sufficient detail and time to affect the drilling operation. Some of the monitored data may be transmitted back to an engineer or geologist at a remote site, but the amount of data transmitted may be limited due to bandwidth limitations. Thus, not only is there a delay in processing due to transmission time, the processing and analysis of the data may be inaccurate due to missing or incomplete data. Drilling operations continue, however, even while awaiting the results of analysis (such as an updated geological model).
A real-time drilling monitor (RTDM) workstation is disclosed in “Drilling Rig Advisor Console,” U.S. application Ser. No. 13/31,646, which is incorporated herein by specific reference for all purposes. The RTDM receives sensor signals from a plurality of sensors and generates single graphical user interface with dynamically generated parameters based on the sensor signals.
Likewise, an intelligent drilling advisor system is disclosed in “Intelligent Drilling Advisor,” U.S. Pat. No. 8,121,971, which is incorporated herein by specific reference for all purposes. The intelligent advisor system comprises an information integration environment that accesses and configures software agents that acquire data from sensors at a drilling site, transmit that data to the information integration environment, and drive the drilling state and the drilling recommendations for drilling operations at the drilling site.